Research Brief: Tracking the spread of the Southern Pine Beetle

Pitch pine forests typical of Acadia

C. Schmitt/Schoodic Institute

Many mountains in Acadia National Park, including Cadillac and Dorr mountains, are covered in forests of pitch pine. These trees, growing at the northernmost edge of the pitch pine’s range in unique association with other plants and animals, are vulnerable to a recently spreading pest, the southern pine beetle.

In “outbreak” conditions, southern pine beetle (Dendroctonus frontalis) can kill large numbers of healthy pines via mass-attack. Because of warming winters, southern pine beetle can now establish and persist farther north than ever before. While the insect has not been detected in Acadia, it has been found in the region. Caroline Kanaskie, a Ph.D. candidate at the University of New Hampshire and 2023 Second Century Stewardship Fellow, has been documenting the spread of southern pine beetle into the Northeast.

Outbreaks of southern pine beetle have occurred at Fire Island National Seashore on Long Island, New York, and individual beetles have been trapped at Cape Cod National Seashore in Massachusetts. Kanaskie has trapped them as far north as Waterboro, Maine. For this project, she will assess the risk posed by advancing southern pine beetle populations to pitch pine in Acadia, as well as in Cape Cod and Fire Island national seashores.

Kanaskie will measure documented risk factors for southern pine beetle outbreaks, including pine stem density and basal area. She will also collect local temperature data from pitch pine-dominated sites. Combined with historical measurements and existing models of southern pine beetle habitat, the analysis will provide information about whether conditions, especially winter minimum temperatures, are suitable to the survival of southern pine beetle in Acadia and other parks.

“While the red spruce may be the most common tree in Acadia, the pitch pine communities of our rocky mountain tops and ridges may have the most lasting imprint on many visitors’ memories, framing the expansive views beyond the lichen-covered granite balds of our “desert” island,” said Acadia National Park biologist Jesse Wheeler. “We know their uniqueness makes our pitch pine forests vulnerable. Caroline’s work will help us understand how threatened these woodlands are to southern pine beetle, and if environmental conditions will allow the beetle to flourish.”

Kanaskie’s final products, including park-specific datasets and recommendations for managing and continued monitoring of southern pine beetles, will help the park prepare for and respond to the presence of southern pine beetle in the future.